In fact, after we ordered ours at 7 p.m. on a Friday, the party seated behind us was all frowns when informed the kitchen had just run out. The dish is not cheap, either.

The 1811 Dictionary of the Vulgar Tongue contains an entry for pig that has surprisingly modern features: Pig: A police officer. A China street pig; a Bow-street officer.

The tongue, it turned out, had wisely been braised separately, and a line of deep-pink cross sections of its musky, unsettlingly tender meat was laid out on the board, too.